The invention described herein relates to the field of military ordnance. In particular it relates to large caliber training ammunition fired from tanks in the arsenal of the United States Army.
The standard gun on the US Army""s main battle tank, the M1A1 Abrams, is a 120 mm smooth bore cannon. This gun is capable of firing a suite of specialized ammunition required on the modern battlefield including high velocity long-rod penetrators, shaped-charged warheads and high explosive rounds. These rounds are inherently lethal, have extremely long ranges and are quite expensive.
For these reasons, the use of these rounds is restricted to the actual battlefield and only the most specialized of training exercise. For general exercises it is advantageous to have training rounds that can emulate the various battlefield ammunition types and incorporate necessary features such as look and feel of the actual device while achieving reduced production costs, reduced range and severely restricted lethality.
Currently, the M865 training cartridge is the Army""s standard 120 mm training projectile for kinetic energy (KE) rounds. It is used to emulate a wide range of tank ammunition including the following tactical projectiles: M829, M829A1, M829A2 and M829A3. The M865 projectile design could be further improved to more closely emulate the appropriate physical characteristics of the foregoing and other tactical projectiles.
The M865 training cartridge is substantially shorter (approximately 4 inches) and lighter (approximately 12 lbs) than the tactical cartridges it is intended to emulate. Specifically, U.S. Army Annex E, Long-Range Kinetic Energy Training Ammunition (LRKE)xe2x80x94120 mm Operational Requirements Document (ORD) for Tank Ammunition states the following: The current training kinetic energy ammunition does not emulate the appearance, handling, and accuracy of the service kinetic energy round.
The smaller size and lighter weight of the M865 training cartridge could result in unrealistic training for the soldiers and could promote the development of habits that could be unsuitable for combat situations. In particular, during training, the soldier becomes accustomed to the reduced weight and shorter overall length of the M865 training cartridge and develops loading techniques that do not apply to tactical ammunition. This adversely affects the soldier""s ability to perform his job efficaciously and safely when using the tactical ammunition.
Space is very limited inside a tank. A soldier training with an M865 training cartridge and then using a tactical cartridge, to which the soldier has had limited exposure, in battle, could cause the cartridge to impact against portions of the interior of the vehicle, e.g., ceiling or walls. The soldier could inadvertently damage the tip of the tactical projectile affecting its accuracy and ability to defeat the target, or worse, drop the projectile after hitting an unanticipated surface within the tank during the heat of battle.
The current US Army requirement has established that kinetic energy training projectiles fired at all Army Training Facilities worldwide must be on the ground before reaching an 8000-meter limit when fired at a 10-degree gun elevation and be accurate out to 3000 meters. The M865 training cartridge is capable of meeting the 8000-meter requirement, however, the U.S. Army ORD states that the M865 training cartridge cannot be fired accurately beyond 2500 meters.
Thus, there is a great and still unsatisfied need for a solution to the training rounds for 120 mm tank guns or other similar weapons, which addresses the foregoing concerns.
The long range trainer (LRT) of the present invention satisfactorily meets this need by addressing the shortcomings of the M865 training cartridge and providing a training round that meets all the current US Army requirements. In particular, the long range trainer meets the guidelines for target impact dispersion at ranges beyond 3000 meters, displaying accuracy and round-to-round precision necessary to meet the current requirements.
The long range trainer design enables its projectile to be range limited to less than 8000 meters when fired at a 10-degree gun elevation. In addition, the long range trainer will provide positive training for the soldier by having the similar exterior physical appearance, meeting the weight requirements and being accurate out to 3000 m. It is estimated that the long range trainer will be comparable in cost to the existing trainer (M865).
The long range trainer achieves its goals by incorporating the following characteristics: The physical parameters of the new cartridge more closely duplicate that of the current tactical tank cartridges including the M829, M829A1, M829A2 and M829A3 cartridges. Specifically, the overall cartridge weight of the new trainer is increased and is within the requirements of the ORD. The heavier weight is achieved by utilizing a longer sabot that has a similar profile to the tactical projectile. This sabot can be fabricated from either aluminum or steel. The steel sabot allows a closer weight match to the tactical cartridge and also achieves savings compared to aluminum sabots that are used in the M865 training cartridge.
The overall length of the long range trainer is also increased to be almost identical (or generally similar) to that of the kinetic tactical cartridge, to have an almost identical exterior profile, and to meet the Army weight and profile requirements. These advantages provide positive and proper training to the soldier.
The long range trainer is designed to have a three-piece aluminum or steel sabot with a similar exterior profile to the kinetic energy tactical sabot. The long range trainer sabot is designed to encapsulate and support a light-weight steel rod and aluminum fin or cone. After gun launch, the sabot is discarded and the light-weight projectile (steel rod and aluminum fin) travel downrange to the target. Due to the light-weight of the projectile it does not travel more than 8000 meters without ground impact, when fired from a gun with ten degrees elevation, but has the ability to meet accuracy requirements out to a range of approximately 3000 meters to 4000 meters.
Additionally, as a result of the in-flight projectile being encapsulated at least in part in the sabot, it will not be subject to differential pressures (xe2x88x92dp) and will not have bending problems that most kinetic energy projectile rods have, which cause accuracy problems in-flight. Differential pressures are caused by uneven propellant burning and therefore may bend the projectile rod at shot start that is inside the propellant bed. All the tactical projectiles and the M865 have rods that are inside the propellant bed of the cartridge. Since the long range trainer projectile is not inside the cartridge case it is not subject to this problem.
The long range trainer design also allows for the use of a fin in place of a high drag cone, which will also help with accuracy and dampen any pitch and yaw when the projectile is launched.
In addition, the benefits of the long range trainer are achieved with minimal changes to the current M865 production line. The projectile assembly does not intrude into the cartridge case, allowing less energetic and less expensive M14 propellant versus other conventional kinetic propellant such as JA2 to be used. Therefore, except for the in-bore projectile, all other trainer cartridge components will be the same as the M865. As a result, the cost of the long range trainer is expected to be comparable to, or less than that of the current M865 trainer.